Center fork stop motion



June 1945- E. c. NXCHOLS CENTER-FORK STOP MOTION Filed May 1:5, 1944 24 flu. j

INVENTOR.

v 5F 0 mm W A D m M E l in Fig. 1;

Patented June '12, 1945 H y I CENTER. FORK s ror nro rroivf I j Edward 'GLLNichols, Upton, Massassignorto rationof Maine Draper. Corporation, Hopeflale,..M'ass.,. a corpo- Application May lls, 1944-, strains-535,450

" [2. Claims. (onset-37c),

The present invention relates generally to antomatic looms and, as illustrated herein; relates more particularly to'improvements in centerfork stopmot'ions for such looms;

' Itisnow usual practice in looms for weaving certaintypesof fabrics; forexampl'e. rayon, to provide a center fork stop mechanism wherein the-filling fork is" raised periodically topermit the shuttle to pass and-ftlien to fall and-feelg-for the filling and-to--detect its presence or absence in the shed. In the event that the filling is absent, the filling fork will start a train of mecha- 'nism into operation which in turn will stop the loom.

such raising will occurin excess of 200 times per minute. The fillingv fork under certain condi tions may overthrow and hence will not properly perform the detecting operation. While this condition seldom occurs it, nevertheless, presents a serious problem since the filling fork may cause fork marks to be made in the fabric or will form an excessive loop under the filling fork and will form a fillingloop in the woven fabric. In other cases defective cloth results.

One object of the present invention, accordingly, is to provide a construction whereby the above mentioned difliculties will be avoided. To this end, the filling fork is arranged to engage a stop as it approaches the upper limit of its movement, said stop being arranged to engage an armon the fillingfork mechanism, said stop being resilient and arranged to yield slightly when engagedlby said arm.

With the'above and other objects and features in view, the invention will now be describedwith particular reference to theaccompanying drawing which illustrates a preferred embodiment of the invention and in which:

Fig. 1 is a perspective view of a. center fork mechanism to which a preferred embodiment of the invention is applied;

Fig. 2 is a plan view of the construction shown Fig. 3 is a view i'n'front elevation; and

The raising of the filling fork must occur dur-v ing-each pick and in modern high speed looms,

drawing, onlya portion of the lay IUis shown and the parts of 'thel'oom' not shown may be of usual construction and formnopart of the present invention.

'Ihe presence or: absenceof a filling thread is detected by a filling for k I2 and upon. detection by the fork IZLat-thewabsence of 'afill'ing thread, the-stop. motion disclosed in said Letters Patent is actuated to efiect stopping of the loom. The filling: forkl 2 i's pivotallymounted in a bracket [4 fixed in any suitable manner to the front face of the lay beam. The filling fork I 2 is provided with tines 16 which are raised above the path of movement of the shuttle. The fork I2 is raised positively by a reciprocating cam or cam member l8 but is lowered, after the shuttle is passed, by,

gravity assisted by a spring 20, The filling fork described above is old and well known in the art.

The parts of the mechanism for raising the fork [2 include a. bell crank lever (not shown) which is rocked in one direction by a cam mechanism shown and described in the above mentioned Letters Patent. An actuating rod 22 is connected to the bell crank lever at one end and at its other end is mounted for reciprocating movement in an opening formed in the lower end portion of the bracket M. The rod 22 carries the fork lifting cam l8 referred to above. The cam I8 is fixed to the rod 22 by suitable set screws 24 and is provided with a cam surface 26, 26 which is interrupted by a stop shoulder 28. The rod 22 is moved to the left by the bell crank lever hereinbefore referred to and the rod 22 is moved in the opposite direction by a spring 30. Thus, if the fork is free to move downwardly into a fork receiving slot 38 in the lay beam l0 because of filling failure, a crank arm 34 fixed to the fork l2 will enter behind the stop 28 and prevent further movement of the rod 22 and efiect stoptioned Letters Patent.

Fig. 4 is a perspective detail view of the stop mechanism.

The present invention is illustrated as applied 7 to a center fork stop motion of the type described and claimed in United'States Letters Patent No. 1,865,930 granted July 5, 1932, on an application filed in the name of Verner Lindsjo to which ref erence may be had for a detailed description of the parts not shown or described herein. In the The fork I2 and its associated movable parts are made as light as possible consistent with necessary strength and rigidity. This is necessary to reduce inertia of the parts and thus permit the fork to be stopped without the use of heavy springs; Under normal conditions, a stop spring 36 is arranged to be engaged by, the arm 34 as it approaches the upper limit of its movement. This spring exerts only light pressure on the arm 34 and only aids in starting the fork l2 in its downward movement. The fork l2 cannot move too rapidly into contact with the filling which lays across the fork recess 38 or the fork will cause the filling to break or to form a large loop'which will not prevent movement of the fork into the recess.

To avoid overthrow of the fork [2, it is necessary to provide a stop member which will not cause any increase in the downward speed of the fork during its feeling movement. As illustrated, a stop 40 is provided which is arranged to be engaged by the arm 34 shortly after thearm has engaged the loop of the stop spring 36. The stop it is in the form of a wire which is sufficiently large in diameter to resist bending under impact of the fork arm 34. One end of the stop 40 is bent to receive a bolt 42 and which end is clamped in position by a nut 44. The wire extends generally upwardly from the bolt 42 so that the portion thereof engaged by the arm 34 is in a suitable position to be engaged thereby. The other end of the stop is bent downwardly and extends under the bracket M. Thus if the nut 44 becomes loosened, the stop 40 cannot swing upwardly about the bolt 42 as pivot and thus injure the cloth being woven. The stop member 40, therefore, is effective to prevent overthrow of the fork !2. The fork 12 will not rebound appreciably upon striking the stop since the stop is sufiiciently rigid to prevent such action.

The present stop is illustrated as being formed of wire but it is apparent that it may be formed of other materials and in other forms if so desired.

Having thus described my invention what I ent of the United States is:

1. In a center fork stop motion for looms, a

lay, a center fork, a supporting bracket on which said fork is pivoted, a cam member reciprocating in timed relation with the movement of the lay, a crank arm on said center fork engaging said cam member and oscillating said fork, and a stop member having one end clamped by a bolt on the lay and having its other end located under said bracket and engaged thereby to prevent upward movement of said stop member when said bolt becomes loose, said stop member being arranged to be engaged by said crank arm when it approaches one limit of its oscillating movement and thereby preventing overthrow of said center fork.

2. In a center fork stop motion for looms, a lay, a center fork, a bracket fixed to the lay and on which the center fork is mounted for pivotal movement, a cam reciprocating in timed relation to the movement of the lay, a crank arm on said center fork engaging said cam member and oscillating said fork, and a resilient stop member fixed at one end to the lay and having its other end located under said bracket, said stop member being arranged to be engaged by said crank when the center fork approaches the upper limit of its oscillating movement thereby preventing overthrow of said center fork.

EDWARD C. NICHOLS. 

